Written by: Noelle A. Koo (11th grade / Ashburn, VA USA) and Alisha Thakur (11th grade / Ashburn, VA USA)
Recent technological developments have made gene editing a clinical reality. However, this power has led to debate over what could be done vs. what should be done. In the case of inherited metabolic disorders, they are usually autosomal recessive, which means that both parents must be a carrier for their child to have a chance at developing the disease. Assuming both parents are heterozygous carriers of the disease, which means that both parents carry one copy of the “healthy” gene and one copy of the “diseased” gene, then any child of theirs has a 25% chance of inheriting two “diseased” genes, resulting in the disease showing up in the child. Parents have a couple of options with this, each with its own ethical consequences. First and foremost, parents must decide whether or not to have children at all, knowing of the 25% chance of passing on the disease to their offspring. Parents can choose to get a pre-implantation genetic diagnosis, so that only the “healthy” embryos are implanted into the uterus. Another option is to undergo antenatal testing, to find out if the embryo already in the uterus is affected. If the parents go with this option and find out their child is in fact affected with the disease, they will have to make the choice between terminating the pregnancy or letting the child be born with the disease. This raises the tough decision whether it is better to live with the disease or not to live at all. However, it must be considered that a child with the disease would not live a complete life. Yet another option is to simply have the infant checked for the disease after it is born. Now with genetic editing, having the option to choose itself is an ethical dilemma. All these problems, questions, decisions, and consequences must be considered by not only the parents of a child, but by society as a whole.
A study regarding gene editing to repair a gene that was faulty in a human embryo has already been conducted. The faulty gene was one that led to heart failure, and the researchers used an enzyme known as CRISPR/CAS9 as their scissors. These scissors were called “molecular scissors” which the researchers used to snip off the faulty gene inside the embryo’s DNA. Many worried about the ethical concerns and the problematic question of whether designer babies would be able to be made or not. But in the latest tests, it was shown that the treated embryos rejected pieces of DNA that the researchers had added. However, as much as this finding was a huge breakthrough, the researchers showed that some of the embryos were partially edited. This research offered “lessons in how to more accurately wield the CRISPR/CAS9 scissors.” And they reduced the number of embryos only partially edited. A second study was conducted, where the researchers used the sperm from a man who was a carrier of the gene that caused the heart failure, and injected it into the egg of a woman with healthy copies of the gene. While this was happening, the researchers also injected a gene editor into the egg; the gene editor had many components. One component was the scissors, a DNA cutting enzyme called CAS9. Another was a piece of RNA that was needed to direct the scissors to the right place to cut. The results surprised researchers because the cells of the embryo ignored it, but then the embryos used the mother’s clean copy of the genes to mend the cut. This research showed that embryos reject addition of new traits, and that designer babies would be very hard to make, which partially eliminates the major ethical concern.
Article Links:
(1): Gene Editing: A View Through the Prism of Inherited Metabolic Disorders: https://tandfonline.com/doi/full/10.1080/20502877.2018.1443563
(2) Molecular Scissors fix disease-causing flaw in human embryos: https://www.sciencenewsforstudents.org/article/molecular-scissors-fix-disease-causing-flaw-human-embryos#:~:text=Researchers%20used%20%E2%80%9Cmolecular%20scissors%E2%80%9D%20to,can%20lead%20to%20heart%20failure.
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